"""Shared config helpers for the NVIDIA Shield integration."""

import os
from dataclasses import dataclass

from homeassistant.core import HomeAssistant
from homeassistant.helpers import entity_registry as er

from .const import (
    CONF_ADB_HOST,
    CONF_ADB_PORT,
    CONF_ANDROIDTV_ENTITY,
    DEFAULT_ADB_PORT,
    DOMAIN,
)


@dataclass
class AdbConfig:
    """Resolved ADB connection settings for a config entry."""

    host: str
    port: int
    key_path: str


def adb_key_path(hass: HomeAssistant) -> str:
    """Path of the ADB private key for this integration (may not exist yet)."""
    return os.path.join(hass.config.config_dir, ".storage", DOMAIN, "adbkey")


def protocol_cert_paths(hass: HomeAssistant) -> tuple[str, str]:
    """Local (certfile, keyfile) paths for the remote protocol client.

    Mirrors core androidtv_remote's storage pattern: private material under
    ``.storage/<domain>/``. Shared between config-flow pairing and runtime —
    an entry aborts duplicate setup by unique_id (= device MAC), so one pair
    of files suffices per install.
    """
    base = os.path.join(hass.config.config_dir, ".storage", DOMAIN)
    os.makedirs(base, exist_ok=True)
    return os.path.join(base, "client.pem"), os.path.join(base, "client.key")


def discover_adb_host(
    hass: HomeAssistant, androidtv_entity_id: str | None
) -> str | None:
    """Best-effort host for an AndroidTV entity, from its owning config entry."""
    if not androidtv_entity_id:
        return None
    registry = er.async_get(hass)
    entity_entry = registry.async_get(androidtv_entity_id)
    if not entity_entry or not entity_entry.config_entry_id:
        return None
    config_entry = hass.config_entries.async_get_entry(entity_entry.config_entry_id)
    if config_entry:
        return config_entry.data.get("host")
    return None


def resolve_adb_config(hass: HomeAssistant, entry) -> AdbConfig | None:
    """Resolve host/port/key_path for the entry's ADB connection, or None.

    Priority: explicit ADB host/port options > host from the AndroidTV
    entity's own config entry.
    """
    host = entry.options.get(CONF_ADB_HOST) or discover_adb_host(
        hass, entry.data.get(CONF_ANDROIDTV_ENTITY)
    )
    if not host:
        return None
    port = int(entry.options.get(CONF_ADB_PORT, DEFAULT_ADB_PORT))
    return AdbConfig(host=host, port=port, key_path=adb_key_path(hass))